TPS61165 Rset trace/wire resistance compensation?

Adam Mitchell

Prodigy 75 points

Other Parts Discussed in Thread: TPS61165

I am driving a remote LED array approximately 30" away using 24gauge wire.

Vin 12v

10 leds @ Vf 2.75v

Rset .576Ohm for about 350mA

Should I be factoring in the resistance of the wire from the last LED to the Rset resistor or the entire string or at all? 30" of 24 gauge wire has a resistance of about .064 Ohms, not insignificant.

Adam

over 8 years ago

0 Harini Sankabattula over 8 years ago

TI__Intellectual 1780 points

Hi Adam,

Based on this it looks like the long wire is on the load and Rset is closer to the part. So, you don't include long wire resistance in the Iset calculations.

Instead you should include it as part of the load. Additional 350mA * 0.064ohm would come in your boost calculations.

Hope this helps. Feel free to post if there are any additional questions.

Best,
-Harini

0 Adam Mitchell over 8 years ago in reply to Harini Sankabattula

Prodigy 75 points

Hi Harini,

Yes the long wire to the LED array, then long wire back to Rset at the TPS61165.

Ok so its not really going to change anything considering the power that I am already using.

Thank you.

0 Harini Sankabattula over 8 years ago in reply to Adam Mitchell

TI__Intellectual 1780 points

Hi Adam,

Yeah I don't see any issue. For your conditions, an additional 0.064ohm wire resistance should be fine. The boost voltage would just increase by ~22.5mV.

Best,
-Harini

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TPS61165 Rset trace/wire resistance compensation?